SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9089f064b4363bc3dc614c54722321262fa1221e0974b038cabee01a7a25beb' 
  AND token = '/2WXdH3CIsbU19peMfLCJp4rmdLuMCf0EIa28pa1XxI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}